Heretofore, it has been well known to apply corrosion coatings to brake rotors by using the conventional spray, dip-spin and dip-drain coating processes.
Traditional dip-spin and dip-drain coating processes require immersing the workpiece or part in the coating material, thereafter removing the part from the coating material and either spinning the part to remove the excess material or to allow the part to have the excess material drained from the part. Such processes normally produce non-uniform coating thicknesses, material striations on the rotor's outer surface area, and pooling of coating material in the vented areas of the rotor. Moreover, different coating thickness variations cannot be uniformly and consistently applied to different surfaces and areas of the rotors.
It is also not possible to economically mask brake rotor surface areas prior to the use of conventional dip drain and dip spin processes.
Accordingly, in order to overcome the coating thickness variations of different areas on the rotors, as well as the pooling of material, it becomes necessary to conduct costly rework operations such as a secondary operation to grit blast material from these areas after the part is coated to remove material from areas not desired to be coated. Moreover, the coating problems occurring with the dip-spin and dip-drain processes often interferes with corrosion performance and operational functionality of the brake rotors. Additionally, the brake rotor appearance or aesthetics are adversely affected.
Conventional spray processes do not have the capability to assure complete and uniform material coverage with the vented areas of a vented brake rotor which ultimately materially affects the corrosion protection effectiveness. Vented brake rotors often include forged and complex inside surface area configurations which do not easily retain the coating material used in conventional spray processes. Further, traditional air, airless and electrostatic spray processes do not have the ability to apply coating material to all of the rotor's vented upper, lower and side surfaces. Thus, traditional spray processes do not assure that the brake rotor manufacturer's corrosion protection requirements for the vented areas can be satisfied. Also, required functional performances cannot often be satisfied.
Further, conventional spray processes utilizing complex spray gun and nozzle configurations are unable to satisfactorily vary the coating thicknesses on different surfaces of the rotors.
Accordingly, conventional spray, dip drain and dip spin processes are unable to provide a cost effective high quality coating for vented brake rotors, and particularly they have failed to satisfy the increasing corrosion and aesthetic requirements of the automobile manufacturers.